75 CB750 Frame - Engine Options

[J.D.]

Hi there, I happened upon an intact CB750 Frame in good condition, and I was toying with the idea of turning it into a cafe racer. My question is thus - As far as engines go, what are my options? Rather, what year range of cb750 engines would I be able to mount in my frame? For instance, if I purchased a '92 cb750 engine, would it fit in my '75 frame?

Thanks in advance,
J.D.

[Re-run]

The frames changed for every model. So for your 75 frame, a 69-78 motor would bolt right in.
Any other engines will most likely fit BUT you will be doing custom work on the frame to mount the motor.

however, with the amount of parts available for the sohc engines(69-78), I would stick with that. Not only will it be much easier to work on by far but the classic look lends it self to a cafe.

Just fyi, with some porting and cam work, you can get a nice boost in hp. You can go further and get a number of different sized pistons and different rods. You have a number of ignition choices. You can get CR carbs.
Granted all this costs money and still wont get the performance of a cbr600 but you will have a bike with awesome character if done well. Something that will be unique and draw attention.

[J.D.]

Awesome, that answered my question and then some! Thanks a bunch for the information, Re-Run!